Integration of Magnetic Resonance (MR) and Linear Accelerators (LINAC) or
Magnetic Resonance and other modalities of radiotherapy opens new horizons in Radiotherapy by improved lesion targeting, especially for moving organs. In a practical implementation proposal, the LINAC rotates around the patient to hit the gross target volume (GTV) and clinical target volume (CTV) from multiple angles while minimizing the radiation exposure for surrounding tissues. A difficulty is that as the radiation source is moved around the magnet, active and/or passive components of the radiotherapy system may cause magnetic field distortions.
An example of a magnetic resonance imaging system combined with a LINAC is described in WO 2012/063158 A1.
In El-Sharkawy et al., MAGMA. 2006 November; 19(5): 223-236, doi: 10.1007/s10334-006-0050-2 discusses the homogeneity and stability of the static magnetic field in magnetic resonance imaging. Serial field mapping and phased difference imaging correction is used to correct for spatial and temporal field drifting during phase sensitive MR protocols.